DUBAI/VIENNA - Iran held serious discussions with the UN nuclear watchdog on Sunday about issues that are part of an investigation into suspicions Tehran has conducted atomic bomb research, official media reported on Monday.

Iran's envoy to the International Atomic Energy Agency, Reza Najafi, appeared to acknowledge, however, that Tehran had not fully implemented five transparency measures by an Aug. 25 deadline, as agreed with the IAEA in May.

"Iran is in the process of implementing the five agreed steps," the official IRNA news agency quoted him as saying.

Diplomats in Vienna last week told Reuters that Iran had apparently failed to meet the target date for answering IAEA questions about its nuclear program, but that contacts between the two sides were continuing.